Release 4.11 net/ipv4/arp.c

/* linux/net/ipv4/arp.c
 *
 * Copyright (C) 1994 by Florian  La Roche
 *
 * This module implements the Address Resolution Protocol ARP (RFC 826),
 * which is used to convert IP addresses (or in the future maybe other
 * high-level addresses) into a low-level hardware address (like an Ethernet
 * address).
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * Fixes:
 *              Alan Cox        :       Removed the Ethernet assumptions in
 *                                      Florian's code
 *              Alan Cox        :       Fixed some small errors in the ARP
 *                                      logic
 *              Alan Cox        :       Allow >4K in /proc
 *              Alan Cox        :       Make ARP add its own protocol entry
 *              Ross Martin     :       Rewrote arp_rcv() and arp_get_info()
 *              Stephen Henson  :       Add AX25 support to arp_get_info()
 *              Alan Cox        :       Drop data when a device is downed.
 *              Alan Cox        :       Use init_timer().
 *              Alan Cox        :       Double lock fixes.
 *              Martin Seine    :       Move the arphdr structure
 *                                      to if_arp.h for compatibility.
 *                                      with BSD based programs.
 *              Andrew Tridgell :       Added ARP netmask code and
 *                                      re-arranged proxy handling.
 *              Alan Cox        :       Changed to use notifiers.
 *              Niibe Yutaka    :       Reply for this device or proxies only.
 *              Alan Cox        :       Don't proxy across hardware types!
 *              Jonathan Naylor :       Added support for NET/ROM.
 *              Mike Shaver     :       RFC1122 checks.
 *              Jonathan Naylor :       Only lookup the hardware address for
 *                                      the correct hardware type.
 *              Germano Caronni :       Assorted subtle races.
 *              Craig Schlenter :       Don't modify permanent entry
 *                                      during arp_rcv.
 *              Russ Nelson     :       Tidied up a few bits.
 *              Alexey Kuznetsov:       Major changes to caching and behaviour,
 *                                      eg intelligent arp probing and
 *                                      generation
 *                                      of host down events.
 *              Alan Cox        :       Missing unlock in device events.
 *              Eckes           :       ARP ioctl control errors.
 *              Alexey Kuznetsov:       Arp free fix.
 *              Manuel Rodriguez:       Gratuitous ARP.
 *              Jonathan Layes  :       Added arpd support through kerneld
 *                                      message queue (960314)
 *              Mike Shaver     :       /proc/sys/net/ipv4/arp_* support
 *              Mike McLagan    :       Routing by source
 *              Stuart Cheshire :       Metricom and grat arp fixes
 *                                      *** FOR 2.1 clean this up ***
 *              Lawrence V. Stefani: (08/12/96) Added FDDI support.
 *              Alan Cox        :       Took the AP1000 nasty FDDI hack and
 *                                      folded into the mainstream FDDI code.
 *                                      Ack spit, Linus how did you allow that
 *                                      one in...
 *              Jes Sorensen    :       Make FDDI work again in 2.1.x and
 *                                      clean up the APFDDI & gen. FDDI bits.
 *              Alexey Kuznetsov:       new arp state machine;
 *                                      now it is in net/core/neighbour.c.
 *              Krzysztof Halasa:       Added Frame Relay ARP support.
 *              Arnaldo C. Melo :       convert /proc/net/arp to seq_file
 *              Shmulik Hen:            Split arp_send to arp_create and
 *                                      arp_xmit so intermediate drivers like
 *                                      bonding can change the skb before
 *                                      sending (e.g. insert 8021q tag).
 *              Harald Welte    :       convert to make use of jenkins hash
 *              Jesper D. Brouer:       Proxy ARP PVLAN RFC 3069 support.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/capability.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/fddidevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/net.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
#endif

#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/protocol.h>
#include <net/tcp.h>
#include <net/sock.h>
#include <net/arp.h>
#include <net/ax25.h>
#include <net/netrom.h>
#include <net/dst_metadata.h>
#include <net/ip_tunnels.h>

#include <linux/uaccess.h>

#include <linux/netfilter_arp.h>

/*
 *      Interface to generic neighbour cache.
 */
static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
static bool arp_key_eq(const struct neighbour *n, const void *pkey);
static int arp_constructor(struct neighbour *neigh);
static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
static void parp_redo(struct sk_buff *skb);


static const struct neigh_ops arp_generic_ops = {
	.family =		AF_INET,
	.solicit =		arp_solicit,
	.error_report =		arp_error_report,
	.output =		neigh_resolve_output,
	.connected_output =	neigh_connected_output,
};


static const struct neigh_ops arp_hh_ops = {
	.family =		AF_INET,
	.solicit =		arp_solicit,
	.error_report =		arp_error_report,
	.output =		neigh_resolve_output,
	.connected_output =	neigh_resolve_output,
};


static const struct neigh_ops arp_direct_ops = {
	.family =		AF_INET,
	.output =		neigh_direct_output,
	.connected_output =	neigh_direct_output,
};


struct neigh_table arp_tbl = {
	.family		= AF_INET,
	.key_len	= 4,
	.protocol	= cpu_to_be16(ETH_P_IP),
	.hash		= arp_hash,
	.key_eq		= arp_key_eq,
	.constructor	= arp_constructor,
	.proxy_redo	= parp_redo,
	.id		= "arp_cache",
	.parms		= {
		.tbl			= &arp_tbl,
		.reachable_time		= 30 * HZ,
		.data	= {
			[NEIGH_VAR_MCAST_PROBES] = 3,
			[NEIGH_VAR_UCAST_PROBES] = 3,
			[NEIGH_VAR_RETRANS_TIME] = 1 * HZ,
			[NEIGH_VAR_BASE_REACHABLE_TIME] = 30 * HZ,
			[NEIGH_VAR_DELAY_PROBE_TIME] = 5 * HZ,
			[NEIGH_VAR_GC_STALETIME] = 60 * HZ,
			[NEIGH_VAR_QUEUE_LEN_BYTES] = 64 * 1024,
			[NEIGH_VAR_PROXY_QLEN] = 64,
			[NEIGH_VAR_ANYCAST_DELAY] = 1 * HZ,
			[NEIGH_VAR_PROXY_DELAY]	= (8 * HZ) / 10,
			[NEIGH_VAR_LOCKTIME] = 1 * HZ,
                },
        },
	.gc_interval	= 30 * HZ,
	.gc_thresh1	= 128,
	.gc_thresh2	= 512,
	.gc_thresh3	= 1024,
};

EXPORT_SYMBOL(arp_tbl);



int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
{
	switch (dev->type) {
	case ARPHRD_ETHER:
	case ARPHRD_FDDI:
	case ARPHRD_IEEE802:
		ip_eth_mc_map(addr, haddr);
		return 0;
	case ARPHRD_INFINIBAND:
		ip_ib_mc_map(addr, dev->broadcast, haddr);
		return 0;
	case ARPHRD_IPGRE:
		ip_ipgre_mc_map(addr, dev->broadcast, haddr);
		return 0;
	default:
		if (dir) {
			memcpy(haddr, dev->broadcast, dev->addr_len);
			return 0;
		}
	}
	return -EINVAL;
}


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Linus Torvalds (pre-git)
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Timo Teräs
17
15.74%
1
10.00%
Roland Dreier
12
11.11%
1
10.00%
Rolf Manderscheid
4
3.70%
1
10.00%
Al Viro
1
0.93%
1
10.00%
Total
108
100.00%
10
100.00%



static u32 arp_hash(const void *pkey,
		    const struct net_device *dev,
		    __u32 *hash_rnd)
{
	return arp_hashfn(pkey, dev, hash_rnd);
}

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Linus Torvalds (pre-git)
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64.52%
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David S. Miller
8
25.81%
3
60.00%
Eric Dumazet
3
9.68%
1
20.00%
Total
31
100.00%
5
100.00%



static bool arp_key_eq(const struct neighbour *neigh, const void *pkey)
{
	return neigh_key_eq32(neigh, pkey);
}

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static int arp_constructor(struct neighbour *neigh)
{
	__be32 addr = *(__be32 *)neigh->primary_key;
	struct net_device *dev = neigh->dev;
	struct in_device *in_dev;
	struct neigh_parms *parms;

	rcu_read_lock();
	in_dev = __in_dev_get_rcu(dev);
	if (!in_dev) {
		rcu_read_unlock();
		return -EINVAL;
	}

	neigh->type = inet_addr_type_dev_table(dev_net(dev), dev, addr);

	parms = in_dev->arp_parms;
	__neigh_parms_put(neigh->parms);
	neigh->parms = neigh_parms_clone(parms);
	rcu_read_unlock();

	if (!dev->header_ops) {
		neigh->nud_state = NUD_NOARP;
		neigh->ops = &arp_direct_ops;
		neigh->output = neigh_direct_output;
	} else {
		/* Good devices (checked by reading texts, but only Ethernet is
                   tested)

                   ARPHRD_ETHER: (ethernet, apfddi)
                   ARPHRD_FDDI: (fddi)
                   ARPHRD_IEEE802: (tr)
                   ARPHRD_METRICOM: (strip)
                   ARPHRD_ARCNET:
                   etc. etc. etc.

                   ARPHRD_IPDDP will also work, if author repairs it.
                   I did not it, because this driver does not work even
                   in old paradigm.
                 */

		if (neigh->type == RTN_MULTICAST) {
			neigh->nud_state = NUD_NOARP;
			arp_mc_map(addr, neigh->ha, dev, 1);
		} else if (dev->flags & (IFF_NOARP | IFF_LOOPBACK)) {
			neigh->nud_state = NUD_NOARP;
			memcpy(neigh->ha, dev->dev_addr, dev->addr_len);
		} else if (neigh->type == RTN_BROADCAST ||
			   (dev->flags & IFF_POINTOPOINT)) {
			neigh->nud_state = NUD_NOARP;
			memcpy(neigh->ha, dev->broadcast, dev->addr_len);
		}

		if (dev->header_ops->cache)
			neigh->ops = &arp_hh_ops;
		else
			neigh->ops = &arp_generic_ops;

		if (neigh->nud_state & NUD_VALID)
			neigh->output = neigh->ops->connected_output;
		else
			neigh->output = neigh->ops->output;
	}
	return 0;
}

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Linus Torvalds (pre-git)
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Herbert Xu
32
10.70%
2
9.09%
Denis V. Lunev
10
3.34%
2
9.09%
Stephen Hemminger
5
1.67%
1
4.55%
David Ahern
3
1.00%
1
4.55%
Hideaki Yoshifuji / 吉藤英明
3
1.00%
1
4.55%
Al Viro
2
0.67%
1
4.55%
Changli Gao
2
0.67%
1
4.55%
David S. Miller
1
0.33%
1
4.55%
Ian Morris
1
0.33%
1
4.55%
Total
299
100.00%
22
100.00%



static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb)
{
	dst_link_failure(skb);
	kfree_skb(skb);
}

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/* Create and send an arp packet. */


static void arp_send_dst(int type, int ptype, __be32 dest_ip,
			 struct net_device *dev, __be32 src_ip,
			 const unsigned char *dest_hw,
			 const unsigned char *src_hw,
			 const unsigned char *target_hw,
			 struct dst_entry *dst)
{
	struct sk_buff *skb;

	/* arp on this interface. */
	if (dev->flags & IFF_NOARP)
		return;

	skb = arp_create(type, ptype, dest_ip, dev, src_ip,
			 dest_hw, src_hw, target_hw);
	if (!skb)
		return;

	skb_dst_set(skb, dst_clone(dst));
	arp_xmit(skb);
}

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Thomas Graf
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7
6.80%
2
66.67%
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103
100.00%
3
100.00%



void arp_send(int type, int ptype, __be32 dest_ip,
	      struct net_device *dev, __be32 src_ip,
	      const unsigned char *dest_hw, const unsigned char *src_hw,
	      const unsigned char *target_hw)
{
	arp_send_dst(type, ptype, dest_ip, dev, src_ip, dest_hw, src_hw,
		     target_hw, NULL);
}
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EXPORT_SYMBOL(arp_send);



static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
{
	__be32 saddr = 0;
	u8 dst_ha[MAX_ADDR_LEN], *dst_hw = NULL;
	struct net_device *dev = neigh->dev;
	__be32 target = *(__be32 *)neigh->primary_key;
	int probes = atomic_read(&neigh->probes);
	struct in_device *in_dev;
	struct dst_entry *dst = NULL;

	rcu_read_lock();
	in_dev = __in_dev_get_rcu(dev);
	if (!in_dev) {
		rcu_read_unlock();
		return;
	}
	switch (IN_DEV_ARP_ANNOUNCE(in_dev)) {
	default:
	case 0:		/* By default announce any local IP */
		if (skb && inet_addr_type_dev_table(dev_net(dev), dev,
					  ip_hdr(skb)->saddr) == RTN_LOCAL)
			saddr = ip_hdr(skb)->saddr;
		break;
	case 1:		/* Restrict announcements of saddr in same subnet */
		if (!skb)
			break;
		saddr = ip_hdr(skb)->saddr;
		if (inet_addr_type_dev_table(dev_net(dev), dev,
					     saddr) == RTN_LOCAL) {
			/* saddr should be known to target */
			if (inet_addr_onlink(in_dev, target, saddr))
				break;
		}
		saddr = 0;
		break;
	case 2:		/* Avoid secondary IPs, get a primary/preferred one */
		break;
	}
	rcu_read_unlock();

	if (!saddr)
		saddr = inet_select_addr(dev, target, RT_SCOPE_LINK);

	probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
	if (probes < 0) {
		if (!(neigh->nud_state & NUD_VALID))
			pr_debug("trying to ucast probe in NUD_INVALID\n");
		neigh_ha_snapshot(dst_ha, neigh, dev);
		dst_hw = dst_ha;
	} else {
		probes -= NEIGH_VAR(neigh->parms, APP_PROBES);
		if (probes < 0) {
			neigh_app_ns(neigh);
			return;
		}
	}

	if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
		dst = skb_dst(skb);
	arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
		     dst_hw, dev->dev_addr, NULL, dst);
}

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85
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1
4.17%
Jiri Benc
28
8.19%
1
4.17%
Eric Dumazet
23
6.73%
2
8.33%
Changli Gao
11
3.22%
1
4.17%
Américo Wang
10
2.92%
1
4.17%
Jiri Pirko
10
2.92%
1
4.17%
Arnaldo Carvalho de Melo
9
2.63%
1
4.17%
David Ahern
6
1.75%
1
4.17%
Hideaki Yoshifuji / 吉藤英明
6
1.75%
1
4.17%
David S. Miller
4
1.17%
1
4.17%
Al Viro
3
0.88%
1
4.17%
Thomas Graf
2
0.58%
1
4.17%
Eric W. Biedermann
2
0.58%
1
4.17%
Denis V. Lunev
2
0.58%
1
4.17%
Joe Perches
1
0.29%
1
4.17%
Total
342
100.00%
24
100.00%



static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
{
	struct net *net = dev_net(in_dev->dev);
	int scope;

	switch (IN_DEV_ARP_IGNORE(in_dev)) {
	case 0:	/* Reply, the tip is already validated */
		return 0;
	case 1:	/* Reply only if tip is configured on the incoming interface */
		sip = 0;
		scope = RT_SCOPE_HOST;
		break;
	case 2:	/*
                 * Reply only if tip is configured on the incoming interface
                 * and is in same subnet as sip
                 */
		scope = RT_SCOPE_HOST;
		break;
	case 3:	/* Do not reply for scope host addresses */
		sip = 0;
		scope = RT_SCOPE_LINK;
		in_dev = NULL;
		break;
	case 4:	/* Reserved */
	case 5:
	case 6:
	case 7:
		return 0;
	case 8:	/* Do not reply */
		return 1;
	default:
		return 0;
	}
	return !inet_confirm_addr(net, in_dev, sip, tip, scope);
}

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Nicolas Dichtel
18
13.95%
1
25.00%
Al Viro
2
1.55%
1
25.00%
Denis V. Lunev
1
0.78%
1
25.00%
Total
129
100.00%
4
100.00%



static int arp_filter(__be32 sip, __be32 tip, struct net_device *dev)
{
	struct rtable *rt;
	int flag = 0;
	/*unsigned long now; */
	struct net *net = dev_net(dev);

	rt = ip_route_output(net, sip, tip, 0, 0);
	if (IS_ERR(rt))
		return 1;
	if (rt->dst.dev != dev) {
		__NET_INC_STATS(net, LINUX_MIB_ARPFILTER);
		flag = 1;
	}
	ip_rt_put(rt);
	return flag;
}

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17
18.09%
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18.18%
Pavel Emelyanov
10
10.64%
2
18.18%
Hideaki Yoshifuji / 吉藤英明
4
4.26%
2
18.18%
Al Viro
2
2.13%
1
9.09%
Denis V. Lunev
2
2.13%
2
18.18%
Eric Dumazet
1
1.06%
1
9.09%
Total
94
100.00%
11
100.00%

/*
 * Check if we can use proxy ARP for this path
 */


static inline int arp_fwd_proxy(struct in_device *in_dev,
				struct net_device *dev,	struct rtable *rt)
{
	struct in_device *out_dev;
	int imi, omi = -1;

	if (rt->dst.dev == dev)
		return 0;

	if (!IN_DEV_PROXY_ARP(in_dev))
		return 0;
	imi = IN_DEV_MEDIUM_ID(in_dev);
	if (imi == 0)
		return 1;
	if (imi == -1)
		return 0;

	/* place to check for proxy_arp for routes */

	out_dev = __in_dev_get_rcu(rt->dst.dev);
	if (out_dev)
		omi = IN_DEV_MEDIUM_ID(out_dev);

	return omi != imi && omi != -1;
}

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18
15.25%
1
25.00%
Eric Dumazet
5
4.24%
1
25.00%
Changli Gao
4
3.39%
1
25.00%
Total
118
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4
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/*
 * Check for RFC3069 proxy arp private VLAN (allow to send back to same dev)
 *
 * RFC3069 supports proxy arp replies back to the same interface.  This
 * is done to support (ethernet) switch features, like RFC 3069, where
 * the individual ports are not allowed to communicate with each
 * other, BUT they are allowed to talk to the upstream router.  As
 * described in RFC 3069, it is possible to allow these hosts to
 * communicate through the upstream router, by proxy_arp'ing.
 *
 * RFC 3069: "VLAN Aggregation for Efficient IP Address Allocation"
 *
 *  This technology is known by different names:
 *    In RFC 3069 it is called VLAN Aggregation.
 *    Cisco and Allied Telesyn call it Private VLAN.
 *    Hewlett-Packard call it Source-Port filtering or port-isolation.
 *    Ericsson call it MAC-Forced Forwarding (RFC Draft).
 *
 */


static inline int arp_fwd_pvlan(struct in_device *in_dev,
				struct net_device *dev,	struct rtable *rt,
				__be32 sip, __be32 tip)
{
	/* Private VLAN is only concerned about the same ethernet segment */
	if (rt->dst.dev != dev)
		return 0;

	/* Don't reply on self probes (often done by windowz boxes)*/
	if (sip == tip)
		return 0;

	if (IN_DEV_PROXY_ARP_PVLAN(in_dev))
		return 1;
	else
		return 0;
}

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/*
 *      Interface to link layer: send routine and receive handler.
 */

/*
 *      Create an arp packet. If dest_hw is not set, we create a broadcast
 *      message.
 */


struct sk_buff *arp_create(int type, int ptype, __be32 dest_ip,
			   struct net_device *dev, __be32 src_ip,
			   const unsigned char *dest_hw,
			   const unsigned char *src_hw,
			   const unsigned char *target_hw)
{
	struct sk_buff *skb;
	struct arphdr *arp;
	unsigned char *arp_ptr;
	int hlen = LL_RESERVED_SPACE(dev);
	int tlen = dev->needed_tailroom;

	/*
         *      Allocate a buffer
         */

	skb = alloc_skb(arp_hdr_len(dev) + hlen + tlen, GFP_ATOMIC);
	if (!skb)
		return NULL;

	skb_reserve(skb, hlen);
	skb_reset_network_header(skb);
	arp = (struct arphdr *) skb_put(skb, arp_hdr_len(dev));
	skb->dev = dev;
	skb->protocol = htons(ETH_P_ARP);
	if (!src_hw)
		src_hw = dev->dev_addr;
	if (!dest_hw)
		dest_hw = dev->broadcast;

	/*
         *      Fill the device header for the ARP frame
         */
	if (dev_hard_header(skb, dev, ptype, dest_hw, src_hw, skb->len) < 0)
		goto out;

	/*
         * Fill out the arp protocol part.
         *
         * The arp hardware type should match the device type, except for FDDI,
         * which (according to RFC 1390) should always equal 1 (Ethernet).
         */
	/*
         *      Exceptions everywhere. AX.25 uses the AX.25 PID value not the
         *      DIX code for the protocol. Make these device structure fields.
         */
	switch (dev->type) {
	default:
		arp->ar_hrd = htons(dev->type);
		arp->ar_pro = htons(ETH_P_IP);
		break;

#if IS_ENABLED(CONFIG_AX25)
	case ARPHRD_AX25:
		arp->ar_hrd = htons(ARPHRD_AX25);
		arp->ar_pro = htons(AX25_P_IP);
		break;

#if IS_ENABLED(CONFIG_NETROM)
	case ARPHRD_NETROM:
		arp->ar_hrd = htons(ARPHRD_NETROM);
		arp->ar_pro = htons(AX25_P_IP);
		break;
#endif
#endif

#if IS_ENABLED(CONFIG_FDDI)
	case ARPHRD_FDDI:
		arp->ar_hrd = htons(ARPHRD_ETHER);
		arp->ar_pro = htons(ETH_P_IP);
		break;
#endif
	}

	arp->ar_hln = dev->addr_len;
	arp->ar_pln = 4;
	arp->ar_op = htons(type);

	arp_ptr = (unsigned char *)(arp + 1);

	memcpy(arp_ptr, src_hw, dev->addr_len);
	arp_ptr += dev->addr_len;
	memcpy(arp_ptr, &src_ip, 4);
	arp_ptr += 4;

	switch (dev->type) {
#if IS_ENABLED(CONFIG_FIREWIRE_NET)
	case ARPHRD_IEEE1394:
		break;
#endif
	default:
		if (target_hw)
			memcpy(arp_ptr, target_hw, dev->addr_len);
		else
			memset(arp_ptr, 0, dev->addr_len);
		arp_ptr += dev->addr_len;
	}
	memcpy(arp_ptr, &dest_ip, 4);

	return skb;

out:
	kfree_skb(skb);
	return NULL;
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
Linus Torvalds (pre-git)
362
79.74%
19
61.29%
Hideaki Yoshifuji / 吉藤英明
21
4.63%
1
3.23%
Shmulik Hen
21
4.63%
1
3.23%
Herbert Xu
19
4.19%
1
3.23%
Arnaldo Carvalho de Melo
11
2.42%
2
6.45%
David S. Miller
4
0.88%
1
3.23%
Pavel Emelyanov
4
0.88%
1
3.23%
Ian Morris
3
0.66%
1
3.23%
Jan Engelhardt
3
0.66%
1
3.23%
Igor Maravić
3
0.66%
1
3.23%
Al Viro
2
0.44%
1
3.23%
Stephen Hemminger
1
0.22%
1
3.23%
Total
454
100.00%
31
100.00%


EXPORT_SYMBOL(arp_create);



static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return dev_queue_xmit(skb);
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Eric W. Biedermann
27
100.00%
2
100.00%
Total
27
100.00%
2
100.00%

/*
 *      Send an arp packet.
 */


void arp_xmit(struct sk_buff *skb)
{
	/* Send it off, maybe filter it using firewalling first.  */
	NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
		dev_net(skb->dev), NULL, skb, NULL, skb->dev,
		arp_xmit_finish);
}
Contributors
Person
Tokens
Prop
Commits
CommitProp
David S. Miller
12
32.43%
2
25.00%
Shmulik Hen
12
32.43%
1
12.50%
Eric W. Biedermann
8
21.62%
2
25.00%
Linus Torvalds (pre-git)
4
10.81%
2
25.00%
Jan Engelhardt
1
2.70%
1
12.50%
Total
37
100.00%
8
100.00%


EXPORT_SYMBOL(arp_xmit);

/*
 *      Process an arp request.
 */



static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	struct in_device *in_dev = __in_dev_get_rcu(dev);
	struct arphdr *arp;
	unsigned char *arp_ptr;
	struct rtable *rt;
	unsigned char *sha;
	__be32 sip, tip;
	u16 dev_type = dev->type;
	int addr_type;
	struct neighbour *n;
	struct dst_entry *reply_dst = NULL;
	bool is_garp = false;

	/* arp_rcv below verifies the ARP header and verifies the device
         * is ARP'able.
         */

	if (!in_dev)
		goto out_free_skb;

	arp = arp_hdr(skb);

	switch (dev_type) {
	default:
		if (arp->ar_pro != htons(ETH_P_IP) ||
		    htons(dev_type) != arp->ar_hrd)
			goto out_free_skb;
		break;
	case ARPHRD_ETHER:
	case ARPHRD_FDDI:
	case ARPHRD_IEEE802:
		/*
                 * ETHERNET, and Fibre Channel (which are IEEE 802
                 * devices, according to RFC 2625) devices will accept ARP
                 * hardware types of either 1 (Ethernet) or 6 (IEEE 802.2).
                 * This is the case also of FDDI, where the RFC 1390 says that
                 * FDDI devices should accept ARP hardware of (1) Ethernet,
                 * however, to be more robust, we'll accept both 1 (Ethernet)
                 * or 6 (IEEE 802.2)
                 */
		if ((arp->ar_hrd != htons(ARPHRD_ETHER) &&
		     arp->ar_hrd != htons(ARPHRD_IEEE802)) ||
		    arp->ar_pro != htons(ETH_P_IP))
			goto out_free_skb;
		break;
	case ARPHRD_AX25:
		if (arp->ar_pro != htons(AX25_P_IP) ||
		    arp->ar_hrd != htons(ARPHRD_AX25))
			goto out_free_skb;
		break;
	case ARPHRD_NETROM:
		if (arp->ar_pro != htons(AX25_P_IP) ||
		    arp->ar_hrd != htons(ARPHRD_NETROM))
			goto out_free_skb;
		break;
	}

	/* Understand only these message types */

	if (arp->ar_op != htons(ARPOP_REPLY) &&
	    arp->ar_op != htons(ARPOP_REQUEST))
		goto out_free_skb;

/*
 *      Extract fields
 */
	arp_ptr = (unsigned char *)(arp + 1);
	sha	= arp_ptr;
	arp_ptr += dev->addr_len;
	memcpy(&sip, arp_ptr, 4);
	arp_ptr += 4;
	switch (dev_type) {
#if IS_ENABLED(CONFIG_FIREWIRE_NET)
	case ARPHRD_IEEE1394:
		break;
#endif
	default:
		arp_ptr += dev->addr_len;
	}
	memcpy(&tip, arp_ptr, 4);
/*
 *      Check for bad requests for 127.x.x.x and requests for multicast
 *      addresses.  If this is one such, delete it.
 */
	if (ipv4_is_multicast(tip) ||
	    (!IN_DEV_ROUTE_LOCALNET(in_dev) && ipv4_is_loopback(tip)))
		goto out_free_skb;

 /*
  *     For some 802.11 wireless deployments (and possibly other networks),
  *     there will be an ARP proxy and gratuitous ARP frames are attacks
  *     and thus should not be accepted.
  */
	if (sip == tip && IN_DEV_ORCONF(in_dev, DROP_GRATUITOUS_ARP))
		goto out_free_skb;

/*
 *     Special case: We must set Frame Relay source Q.922 address
 */
	if (dev_type == ARPHRD_DLCI)
		sha = dev->broadcast;

/*
 *  Process entry.  The idea here is we want to send a reply if it is a
 *  request for us or if it is a request for someone else that we hold
 *  a proxy for.  We want to add an entry to our cache if it is a reply
 *  to us or if it is a request for our address.
 *  (The assumption for this last is that if someone is requesting our
 *  address, they are probably intending to talk to us, so it saves time
 *  if we cache their address.  Their address is also probably not in
 *  our cache, since ours is not in their cache.)
 *
 *  Putting this another way, we only care about replies if they are to
 *  us, in which case we add them to the cache.  For requests, we care
 *  about those for us and those for our proxies.  We reply to both,
 *  and in the case of requests for us we add the requester to the arp
 *  cache.
 */

	if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
		reply_dst = (struct dst_entry *)
			    iptunnel_metadata_reply(skb_metadata_dst(skb),
						    GFP_ATOMIC);

	/* Special case: IPv4 duplicate address detection packet (RFC2131) */
	if (sip == 0) {
		if (arp->ar_op == htons(ARPOP_REQUEST) &&
		    inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
		    !arp_ignore(in_dev, sip, tip))
			arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
				     sha, dev->dev_addr, sha, reply_dst);
		goto out_consume_skb;
	}

	if (arp->ar_op == htons(ARPOP_REQUEST) &&
	    ip_route_input_noref(skb, tip, sip, 0, dev) == 0) {

		rt = skb_rtable(skb);
		addr_type = rt->rt_type;

		if (addr_type ==